1. Field of the Invention
This invention concerns mouthguards intended to be worn by athletes and other persons engaged in physical activities which might result in occlusal or craniofacial stress and more particularly concerns a method for fitting a protective mouthguard blank adapted to be custom fitted in-situ to an individual athlete/patient.
2. Description of the Prior Art
Athletes and particularly football players, boxers and basketball players, are exposed to trauma from facial blows which may cause damage to the individual. To reduce the hazards of such facial trauma injuries, a variety of protective mouthguards have been developed for use by athletes and others. Medical and dental patients occasionally require protective mouthguards. These prior art protective mouthguards for athletes/patients can be defined in several categories. The designation "athlete/patient" herein is intended to identify any user of the invention.
First category: There is a universal protective mouthguard, to be worn as received without any adaptation to an individual user. These First category protective mouthguards are shaped from rubber or other plastic material and which conforms generally to the configuration of an average upper dental arch and includes a channel having a base, an inner wall and an outer wall. Such universal protective mouthguards tend to fit loosely and function primarily to distribute the physical stresses from a facial blow over a wide area. Such universal protective mouthguards are not easily retained by the athlete/patient and are frequently dislodged as a result of the blow or blows which they were intended to resist.
Second category: There are custom cast-fitted, molded devices, prepared for each individual athlete/patient by initially obtaining an impression of the athlete/patient's dental arch and upper teeth and preparing from the impression a plaster (sometimes called "stone") cast corresponding to the individual athlete/patient's dental arch and upper teeth. The protective mouthguard is molded from rubber or plastic against the plaster (stone) cast and thereafter is introduced into the athlete/patient's mouth where it achieves good retentive characteristics and provides superior dental protection. The expense and time requirement for such custom fitted, molded protective mouthguards is substantial, requiring services of skilled dental personnels.
Third category: There are universal blanks, much like the universal mouthguard of the First category, which are fabricated from post-formable, thermoplastic substances which can be molded and shaped, when needed, by the athlete/patient or by skilled dental personnel to conform more accurately to the athlete/patient's dental arch. The universal blanks for these in-situ custom-fitted mouthguards comprise a generally U-shaped channel having a base, an inner wall and an outer wall. The loose-fitting universal blank is heated to soften the thermoplastic blank, while warm, is fitted against the teeth of the athlete/patient by the athlete/patient or by skilled dental personnel. The resulting in-situ custom-fitted protective mouthguard has good retention characteristics but has a number of shortcomings:
1. The overall configuration of the prior art universal formable blank is a U-shape, whereas the normal dental arch is more of a V-shape;
2. The universal formable blank has a coplaner base from which an outer wall and an inner wall are extended generally vertically. The maxillary incisor inclination of an athlete/patient is not generally vertical to the athlete/patient's occlusal plane but instead rises at an acute angle with respect to the occlusal plane. Substantial compressive movement of the thermoplastic outer wall of Third category mouthguards is required to conform with the athlete/patient's incisors.
Similarly the lingual maxillary incisor surface of an athlete/patient is not perpendicular to the athlete/patient's occlusal plane but rises at an acute angle with respect to the occlusal plane. Conformation of the thermoplastic inner wall of Third category mouthguards also requires compressive movement of the inner wall.
The vertical walls of the Third category mouthguards terminate at the level of the dental-gingival interface and the outer vertical walls also terminate at the dental-gingival interface.
The in-situ custom-forming of Third category mouthguards occurs by inwardly applied pressures, that is, pressures applied against the athlete/patient's teeth on the lingual surface and the buccal and labial surfaces of the teeth result in a compression of the formable thermoplastic substance against the teeth and against the relatively resilient gingival surfaces. Upon relaxation of the compressive forming pressures, the thermoplastic substance tends to spring back away from the teeth and resilient gingival surfaces.
One embodiment of protective mouthguards for athlete/patients in all three categories includes a contiguous strap extending forwardly from the incisor portion of the mouthguard base. The strap is intended to be fastened to a helmet faceguard so that the protective mouthguard will not be lost when the athlete/patient removes the protective mouthguard for comfort, for convenience, or when the mouthguard is displaced involuntarily upon impact. Such strap connections can be dangerous if the athlete/patient's helmet is removed while a securely-retained protective mouthguard remains in place. The hazard increases as the retention characteristics of the protective mouthguard are improved. The prior art straps have not been reliable in their release tension.